1. Field of the Invention
The present invention relates to imaging devices, such as code readers, digital cameras, or the like, having a photodetector with a two-dimensional light sensitive pixel area.
2. Description of the Related Art
As imaging devices with a two-dimensional photodetector, such as a CCD (Charge-Coupled device) area sensor, optical information readers have been used. The optical information readers aim at reading optically readable information, such as a barcode, a two-dimensional code, or other types of information.
Specifically, the optical information readers are operative to:
pick up, through their reading windows, an image of a target containing a barcode by the two-dimensional photodetector;
binarize the picked-up image to obtain code data of the barcode; and
decode the code data.
Such two-dimensional photodetectors normally have a two-dimensional light-sensitive pixel area composed of CCDs (pixels) vertically and horizontally arranged in matrix. The light-sensitive pixel area of each two-dimensional photodetector normally has a 3:4 CCD aspect ratio (vertical to horizontal ratio).
Let us consider a case where a user wants to read, with the use of an optical information reader, a target barcode storing therein a comparatively large amount of data and having a relatively large length (width) across its bars and spaces compared with other normal barcodes.
In this case, when the user locates the optical information reader such that the reading window closely faces the target barcode as is the case of reading a normal barcode, the whole of the target barcode may extend far beyond the field of view (FOV) of the two-dimensional photodetector.
In order to avoid the extension of the target barcode beyond the FOV, even if the user moves the optical information reader to separate the reading window from the target barcode such that the whole of the target barcode contains within the FOV, the image of the target barcode would be picked up by the photodetector with its size being reduced. This may cause the resolution of the optical information reader to deteriorate, and therefore the reading performance of the optical information reader may deteriorate.
For overcoming these problems set forth above, Japanese Unexamined Patent Publication No. 2002-117372 discloses barcode generating systems configured to generate a barcode whose size can be contained within the FOV of a barcode reader. The disclosed barcode generating systems however cannot generate barcodes each of which stores therein a comparatively large amount of data and has a relatively large length (width) across its bars and spaces. Specifically, it is difficult to provide ultimate solution to these problems.
Similarly, as imaging devices with a two-dimensional photodetector, digital cameras have been used for taking images of landscapes and/or people. Some of the digital cameras have a function of taking panoramic images whose width (horizontal length) is longer than its height (vertical length). For example, Japanese Unexamined Patent Publication No. H10-341361 discloses digital cameras configured to:
generate image data of a target with the size corresponding to the light sensitive pixel area of the two-dimensional photodetector; and
delete part of the image data corresponding to one-quarter region of either side of the light sensitive pixel area in its height direction (vertical direction) to generate panoramic image data whose aspect ratio is 3:8.
When taking a target barcode storing therein a comparatively large amount of data and having a relatively large length across its bars and spaces compared with other normal barcodes, the disclosed digital cameras however cannot effectively use the light-sensitive pixel area of the two-dimensional photodetector, which may cause the resolution of the digital cameras to deteriorate.